Answers

The only way to manually terminate Metro-style apps is through task manager. When a user switches away from a Metro-style app, the app is given 5 seconds to perform any cleanup work it might need to do like finish saving state, and after
those 5 seconds, the app will be suspended, at this point the app is still in memory but its not recieving and more CPU cylces. The PC can normally maintain many apps in a suspended state, but if the PC begins running low on memory, it may terminate
suspended apps to free resources so that additional apps can be opened. A terminated app is completely closed, so in addition to not receiving any CPU cycles like a suspended app, it is also no longer resident in memory.